Why? Because US light, tight, sweet oil is absolutely perfect for "making" gasoline. The margins must be huge. I don't know.
Just one example from twitter today:
St Louis Fed doesn't suggest fewer miles being driven due to "drive-sharing apps" and "buying more stuff on line." What's the difference in mileage using Uber or using your own vehicle? What nonsense. "Buying more stuff on line?" Really? No.
We buy a lot of stuff online -- that just frees us up to drive to different places, but doesn't mean we're driving any less. Full-time working / soccer moms know this.
It has to do with LTO being the right kind of oil for making gasoline. [Also for sea-going tankers; IMO 2020.]
October, 2019, St Louis Fed: all-time record for US vehicular miles: